Motor control for switching mechanisms



M 22, 19240 wmms F. A. LUNDQUXST MOTOR CONTROL FOR SWITCHING MECHANISMS Filed Oci. 2, 1919- Patented July 22, 1924.

. UNITED STATES PATENT oFF cE.

FRANK A. LUNDQUIST, OF CHICAGO, ILLINOIS, ASSIGNOR, BY MESNE ASSIGNIVIIEN'TS,

' TO HENRY S. CONRAD, TRUSTEE.

MOTOR CONTROL FOR'SWITCHING MECHANISMS.

Application filed October 2, 1919. Serial No. 828,078.

To all whom it may concern:

Be it known that I, FRANK A. LUNDQUIST, a citizen of the United States of America, and a resident of Chicago, county of Cook, and State of Illinois, have invented certain new and useful Improvements in Motor Controls for Switching Mechanisms, of which the following is a specification.

My inventlon relates to motor control for switching mechanisms, and particularly for means of controlling the motors used in automatic telephone exchanges. The object is to bring about improvements in such exchanges.

In the accompanying drawings Fig. 1 is a diagram of the operative parts involved in the present invention;

Fig. 2 is a similar diagram in which some additional apparatus is inserted in intermediate stages of the operation; I

Fig. 3 is an enlarged longitudinal section of the valve used;

Fig. 4 is a section on line 4=--4 of Fig. 3;

Fig. 5 is a section, partly in. elevation, of the motors;

Fig. 6 is a section position; and

Fig. 7 is a section of the sylphon expanded.

The system here involved is an electropneumatic one in which certain motors are operated by air pressure, and these motors are controlled thru a magnet having windings 11 and 12. The Wires 13 and 14 extend to a local station and are there connected to any form of device by which they may be connected together so as to complete an electrical circuit for the magnet. thru the battery X and the wires 13 and 1 1. Ordinarily, the wires 13 and 14 are connected to a calling device which, when operated, makes and breaks the circuit thru the magnet 12-13 about 10 or more times per second, and the apparatus to be described is intended to operate when electrical impulses flow at that rate thru the magnet. While a calling device such as indicated isordinarily used, the actual means employed to send impulses thru the magnet is immaterial.

A general air supply pipe is shown at 15, and to this pipe is connected a valve casing 16. Inside .of the casing 16 are valves 17 and 18 which have short stems projecting toward each other. The valve 18 has a of the sylphon in normal stem 19 which extends to the exterior of.

the casing 16 and is adapted to be engaged by some lever or arm as will be indicated later. At one side of the casing 16 is a pipe 20 which leads to a motor or to some other valve as occasion may require. With air under pressure entering the pipe 15, the valve 17 normally rests on its seat and no alr flows from pipe 15 to pipe 20. But if some lever be applied to the stem 19 to lift the valve from its lower position to its seat above, then valve 17 will be lifted from its seat and air will flow from pipe 15 to pipe 20. If, after this has occurred, the lifting force be removed from stem 19, then valves 17 and 18 will return to the position shown in Flg. 3, and air in pipe 20 will exhaust past valve 18 and thru the openings shown around stem 19.

The entire apparatus 16, 17 and 19 will be designated as valve 16 for simplicity of expression. There are other valve constructions of the same kind, each of which will be designated by some character applied to the casing.

Referring to Fig. 5, 31 is a pipe to which compressed air is admitted 'by a valve of the kind described. On the end of this pipe is a head 22, and over this head is a cap 23. When an is admitted to the pipe 31, the cap 23 rlses, and when air is exhausted from that pipe, the cap falls. In the construction shown in Fig. 5, a leaky check valve is shown at 24. This check valve permits air to enter freely so that the cap 23 will move quickly, but it prevents the quick exhaust of the air so that the cap can return only slowly. The entire apparatus is a motor which is quick to act and slow to return. Motors of this type are called slow motors and are arbitrarily indicated as having a conical cap, though the extreme shape of the cap has nothing to do with its operation.

The lower part of head 22 is made coni cal, and in the closed lower end of the cap 23 is a seat 21. lVhen the cap rises to its upper position the head 22 is on this seat. When air is exhaused from over the head, air must enter under the head before the cap can fall. The head resting on seat 21 makes the motor slower to start on its .downward movement, but does not retard that movement after the start is made. This. is in addition to the valve 24, and-serves as an additional means for making the motor slow to return.

Another motor consists of a cap 25 mounted on a stationary part 26 to which an air pipe is connected. In this type of motor there are no restrictions to the flow of a r inward or outward, and the cap moves in either direction with equal facility. It is designated a fast motor in contradistinction to the slow motor before described. It is indicated arbitarily in drawings as not having a conical cap. Both kind of motors will be designated by characters applied to the caps.

A third form of motor is the sylphon shown in section in Figs. 6 and 7. This is a sort of: metallic accordian consisting of diaphragms 27 connected to di sks 28. It expands and contacts by admitt ng and eX- hausting air in a manner which will be readily understood by inspection. It 1s used for short movements instead of the fast motor before described because it is an article already manufactured and is cheap and convenient for the purpose.

In the diagram of Fig. 1, the parts are normally in the position shown. Vvhen a circuit is closed thru the magnet 11-12, the armature 29'is attracted to open valve 16. This permits compressed air to flow from the supply pipe 15 to the sylphon 30, and also thru the pipe 31'to the slow motor 32. The sylphon tilts lever 33 tov permit the normally open valve 34 to close. The motor 32 in rising permits spring 35 to move lever 36 so as to open valve 37 and permit alr to flow thru pipe 38 to the valve 34. The previous closure of valve 34 by reason of the action of the sylphon 30, stops the flow of air at this point.

In automatic telephone exchanges, such a closure of the circuit thru the magnet 1112 is a preliminary step, and is independent of the operation of the calling device. When the calling device is operated, it first breaks and then remakes the circuit, and at the end of its operation it leaves the circuit closed. The apparatus herein described is designed to operate under impulses sent in that order, independent of the mechanism used in sending them. will be assumed that the breaks and remakes at the rate of ten or more per second are repeated two or more times.

When the circuit is broken ,thru the magnet, the armature 29 falls back and permits valve 16 to close. This exhausts the air from the sylphon 30, and permits the spring 39 to open valve 34 and let compressed air flow thru pipe 40 to motors 25 and 41, which immediately rise. When the circuit closes, the valve 34 also closes, and motor 25 immediately falls to its lower position. The next break in the circuit causes the motor 25 to again rise, and the next remake causes it to fall. In this manner the motor 25 responds to the impulses flowing thru the magnet as long as they continue. But the In the following description it memos motor 41 remains elevated under such a proceeding and does not respond. The reason is that the exhaust is choked on the slow motor and it does not have time to fall when air pulsations follow each other at the rate indicated. It is only when there is a distinct pause at the termination of a series of impulses that the motor 41 has time to fall.

The motor 32 receives air thru valve 16 and pipe 31 when armature 29 is attracted, and motor 41 receives air thru valve 34 and. pipe 40 when the armature is retracted, provided the motor 32 is previously operated. When impulses flow thru the magnet as in dicated, both motors receive air enough to keep them elevated. If a series of impulses terminate in a closed circuit thru the magnet, then motor 41 falls but motor 32 does not. If the circuit is broken for more than a very short interval of time, then motor 32 falls back and cuts off the supply of air at valve 37.

In an automatic telephone exchange the various motors described each have certain particular Work to perform, usually against causes air pulsations in pipes 31 and 38 which correspond to the impulses flowing thru the magnet. The motor 25 responds to these pulsations and makes as many strokes as the armature makes vibrations. The motor 41 does not respond to individual pulsations, but holds its advanced position during them and makes one complete stroke for each series of pulsations. The motor 32 holds its advanced position from one series of impulses to another and falls back only when the circuit is broken permanently thru the magnet.

In Fig. 2, part of the duty previously described as put upon motor 32 is transferred to another motor 42 and the pipe 31 runs to this motor instead of to 32. In this case the valve 37 is controlled by motor 42. and the pipe 38 conveys air to both valve 34 and motor 32. The motor 25 is operated as before thru valve 34 and pipe 40, but the motor 41 is controlled thru intermediate motor 43, valve 44 and pipe 45.

The relationship between the operations of the motors 25, 32 and 41 and the impulses fiowing thru the magnet are just the same in Fig. 2 as in Fig. 1. The real difference between Fig. 2 and Fig. 1 is in the insertion of the intermediates 42 and 43. These have to do with the details of the mechanism to be operated, and not with the essential characteristics of the operation here described. The object is to show that the ultimate operation is not changed or affected in any way by the insertion of intermediates such as 42 and 43. In both cases, we. have fast and slow motors independently controlled thru a single armature on the magnet 11-12.

In automatic telephone exchanges, some mechanisms move in only one direction while other mechanisms move first in one d1- rcction and later in another direction. Fast and slow magnets, together with considerable complexity of relays and mechanisms, are involved in these operations. In addltion there is holding mechanism by which the apparatus is retained in advanced position while shifts arebeing made from one switching mechanism to another.

The fast motor 25 and slow motor 41 serve in place of fast and slow magnets, and the motor 32 serves to hold apparatus from one stage of the proceeding to another. As the details of the mechanism to be operated differs in different cases, the present application is limited to the motors and the means for controlling them. They may be connected to any apparatus.

lVhat I claim is:

l. The combination with a magnet provided with electrical connections to a distant station, and two air valves, of means by which upon impulses flowing thru said magnet one of said valves will be opened and closed alternately and means controlled by the operation of said first valve for alternately closing and opening the second valve, said parts being so arranged that when one valve is opened the other is closed.

2. The combination with a magnet provided with electrical connections to a distant station, and three air valves, of means by which upon impulses flowing thru said magnot one of said valves will be held open and the other two valves will be opened and closed alternately with each other.

3. In an electro-pneumatic system, a source of compressed air, two motors, a magnet having an armature responsive to electrical impulses flowing thru said magnet, means for admitting air to one of said motors when the armature is in attracted position and to the other motor when it is in its retracted position, and means for maintaining air pressure on both motors when said armature vibrates in response to a series of impulses flowing thru said magnet.

4. A motor, a source'of compressed air, a magnet having an armature, two air valves which normally shut the air off from said motor when said armature is in its retracted and attracted positions, one of said valves directly operated by' said armature, and means operated by the operation of said first valve for operating the second valve to admit air to said motor when said armature moves from attracted to retracted position.

air pressure, and a port closed by said motor at the end of such movement serving to delay the return of the motor to normal position.

6. The combination with a magnet provided with electrical connections to a distant station, and a plurality of air valves, of means by which upon impulses flowing through said magnet a portion of said .plurality of air valves will be held open and two of said plurality of air valves will be opened and closed alternately with each other.

7 In an electro-pneumatic system, a source of compressed air, two motors, a magnet having an armature responsive to electricalimpulses flowing through said mag net, said armature admitting air to one of said motors when in attracted position and to the other motor when in its retracted position to rapidly operate said motors alternately with each other in response to said impulses.

8. In an electro-pneumatic system, two motors, a magnet having an armature, said armature rapidly vibrated in response to electrical impulses, said motors operated alternately with each other in response to the vibration of said armature, each of said motors being operated once for each vibration of said armature.

9. In an electro-pneumatic system, four motors, a magnet having an armature, said armature rapidly vibrated in response to electrical lmpulses for maintaining two of said motors in operated position and for rapidly operating the other two of said motors alternately with each other and each of the last mentioned motors being operated once for each vibration of said armature.

10. In an electro-pneumatic system, three pneumatic motors, a magnet having an armature, said armature responsive to impulses sent through said magnet for causing the operation of one of said motors as many times as there are impulses sent through said magnet, for causing the operation of another of said motors once for each series of impulses, and for causing the operation of the third of said motors once for a plurality of series .of impulses.

11. In an electro-pneumatic system,.four pneumatic; motors, a magnet, and means by which upon impulses being sent through said magnet one of said motors will make one operation for each series of impulses, another of said motors will make one opera tion for a plurality of series of impulses, and the third and fourth motors will make as many operations as there are impulses, said third and fourth motors operating al ternately with each other.

12. In an electro-pneumatic system, a plurality of fast and a plurality of slow pneumatic motors, a magnet having an armature, means for operating one of said fast and one of said slow motors when the armature is in attracted position and for operating another of said fast and another of said slow motors when the armature reaches its retracted position.

13. In an electro-pneumatic system, a plurality of fast and a plurality of slow pneumatic motors, a magnet having an armature, means for operating one of said fast motors and a plurality of said slow motors When the armature is in attracted position and for operating another of said fast motors and a plurality of said slow motors when the armature reaches its retracted position.

14. In an electro-pneumatic system, a source of compressed air, tWo pneumatic motors, a magnet having an armature responsive to electrical impulses for changing said impulses into corresponding impulses of air, said motors rapidly operated alternately with each other in response to said impulses of air.

15. The combination with a magnet provided With electrical connections to a distant station, and two air valves, of means by Which upon impulses flowing through said magnet one of said valves Will be alternately opened and closed, means controlled by the opening of the first valve for closing the second valve, and said means controlled by the closure of the first valve for opening the second valve.

FRANK A. LUNDQUIST. 

